Endothelin biological actions

BIOLOGICAL ACTIONS OF ENDOTHELIN Cardiovascular system Other systems Endothelin interactions... 

The biological actions of ET-2 are, for the most part, similar to those of ET-1 but have been studied less extensively. The activity profile of ET-3 is different, this being ascribed to receptor subtype affinity (see section on endothelin receptors). The big endothelins are considerably less potent and rely to a large extent on conversion to their mature forms for activity. 

Endothelin has many other biological actions, but among the most important of these are the effects on the airways, the gastro-intestinal tract, the kidney and the central nervous system. In addition to its effects on the pulmonary circulation, endothelin has marked effects on non-vascular airway smooth muscle. ET-1 is a potent constrictor of guinea-pig isolated trachea, upper bronchus and parenchyma [35]. ET-2 and ET-3 also contract isolated guinea-pig trachea, although ET-3 is less potent than the other two isoforms [36]. Endothelin contracts bronchial smooth muscle from a... 

Endothelin has been implicated in myocardial infarction, coronary vasospasm and re-stenosis subsequent to percutaneous transluminal coronary angioplasty. The potent, prolonged coronary vasoconstrictor and mitogenic actions of endothelin are well-documented (see earlier section) and thus endothelin is certainly able to produce the biological effects seen in these disease states. Although a reduction in infarct size has been demonstrated in a rat model of myocardial infarction with an endothelin antibody [185], and with phosphoramidon [186], the argument for a role for endothelin in ischaemic heart disease has been based mainly on the finding of increased plasma endothelin levels in patients with myocardial infarction [187-190], coronary vasospasm [191, 192] and re-stenosis post-PTCA [193-195]. 

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